高强韧耐蚀Ti90钛合金热变形本构方程的建立

Establishment of Hot Deformation Constitutive Equation of Ti90 Titanium Alloy with High Strength and Toughness and Corrosion Resistance

采用Gleeble-3800热模拟试验机,在800~1050℃、应变速率0.1~10 s^(-1)、变形程度75%的条件下对锻态Ti90钛合金进行了等温热压缩变形行为研究。结果表明,Ti90钛合金的峰值应力随变形温度的升高以及变形速率的降低而减小。950℃以下时,合金的流变应力随应变增大迅速降低,动态软化行为作用显著;950℃以上时,流变应力基本保持稳定。计算获得Arrhenius方程系数与应变之间的函数关系,使用线性回归的方法建立了Ti90钛合金的Arrhenius本构模型,计算该合金的热激活能为706.1973 kJ/mol。对比计算与试验获得的流变应力曲线,本构方程计算值与试验值基本相符,说明该模型具有较好的预测精度,可以用来指导有限元模拟及生产过程的工艺参数选择。

The isothermal compression deformation behavior of forged Ti90 titanium alloy was studyed under conditions of 800~1050℃,strain rate of 0.1~10 s^(-1),and deformation degree of 75%,using Gleeble-3800 thermal simulation testing machine.The results indicate that the peak stress of Ti90 titanium alloy decreases with the increase of deformation temperature and the decrease of deformation rate.At temperatures below 950℃,the flow stress of the alloy rapidly decreases with increase of strain,and the dynamic softening behavior plays a significant role.At temperatures above 950℃,the flow stress remains stable.The functional relationship between Arrhenius equation coefficients and strain was calculated.The Arrhenius constitutive model of Ti90 titanium alloy was established using linear regression method,and the thermal activation energy of the alloy was calculated to be 706.1973 kJ/mol.Compared with the flow stress curve obtained from calculation and test,the calculated value of constitutive equation is basically consistent with the test value,which indicates that the model has good prediction accuracy and can be used to guide the finite element simulation and the selection of production process parameters.